Page 68 - PC 101 practical notes 24-25..
P. 68
MANSOURA NATIONAL UNIVERSIY
PHARM D- CLINICAL PHARMACY LEVEL I PHARM. ANAL. CHEM. I (PC 101)
M Mo oh hr r' 's s M Me et th ho od d .
.
It is a type of precipitation titration that depends on the formation of
a colored secondary ppt at the end point.
Main features of Mohr's method:
-
-
-
-
• Sample: Cl , Br (Not for I or SCN ).
• Type of titration: Direct titration.
• Standard Solution: Standard AgNO 3.
• pH: Neutral or slightly alkaline. (pH ≈ 6.5 -9).
• Indicator: 1 ml of 5% Pot. Chromate (K 2CrO 4)
solution.
• Color at E.P.: First permanent darkening of the yellow
chromate color [due to the formation of
Ag 2CrO 4 (brick red ppt) at the end point
leading to darkening of the solution].
68 | P a g e
